"What's the matter with you guys? Time machines are nothing but trouble - even we know that!"
--Col. O'Neill to Thor, Stargate SG-1

Wait, haven't you read this page before?

Ever since I was young I've had this fascination with time travel. But there's a ton of sites out there already dedicated to that sort of thing, so I'm going to concentrate here on one thing in particular, namely time loops. That is, the idea of reliving a day (or other particular length of time) over and over and over again.

Just for the heck of it, I've decided to try and compile together a list of instances when this has occurred, and how the writers dealt with the phenomenon (in at least some detail). Note that using time travel to simply repeat an instance of time doesn't count; sure, Marty McFly lived through November 12, 1955, on two occasions, in the Back to the Future trilogy... but he was a separate person each time and able to alter his prior actions.

The list is chronological, with the exception of putting "Groundhog Day" first... the Star Trek: TNG episode actually aired BEFORE this well known movie. I am also aware of the cancelled series "DayBreak" (2006), where a time loop was the main plot point (Detective Hopper keeps repeating the same day, with his injuries carrying over to the start of the loop). In fact, after seeing only two episodes, I had issues with the lack of a reason and limited potential character development myself. "Russian Doll" (2019) seems to have done better, but I haven't seen that.

Oh, one more thing. In March 2003, the group Improv Everywhere created a real life twelve iteration time loop, in a Manhattan Starbucks, as a prank. You can read about how well that went on their website here, and it is also apparently part of their book.

Loops I Have Seen

Groundhog Day (February 1993)

The more well known instance of time looping, which usually gets referenced when there's a discussion on the subject. Phil Connors (Bill Murray), a TV weatherman, keeps repeating the same February 2nd over and over.

Doctor Who (October 1980)
Season 18, Episode 6: Meglos, Part II. (Serial 111) Star Trek: The Next Generation (March 1992)
Season 5, Episode 18: Cause and Effect. (Episode 118) Xena: Warrior Princess (October 1997)
Season 3, Episode 2: Been There, Done That. (Episode 48) 7 Days (October 1998)
Season 1, Episode 4: Come Again? (Episode 4) The X-Files (February 1999)
Season 6, Episode 15: Monday. (Episode 131) Charmed (May 1999)
Season 1, Episode 22: Deja Vu All Over Again. (Episode 22) The [new] Outer Limits (July 1999)
Season 5, Episode 16: Deja Vu. (Episode 104) Stargate: SG1 (August 2000)
Season 4, Episode 6: Window of Opportunity. (Episode 72) First Wave (October 2000)
Season 3, Episode 4: Gulag. (Episode 48) Buffy the Vampire Slayer (October 2001)
Season 6, Episode 5: Life Serial. Star Trek: Enterprise (February 2003)
Season 2, Episode 16: Future Tense. Mutant X (January 2004)
Season 3, Episode 11: Possibilities. (Episode 55) Andromeda (October 2004)
Season 5, Episode 6: When Goes Around... (Episode 94) Supernatural (February 2008)
Season 3, Episode 11: Mystery Spot. (Episode 55) Eureka (August 2008)
Season 3, Episode 4: I Do Over. (Episode 29) Haruhi Suzumiya (Summer 2009)
Season 2, Episode 2, 3, 4, 5, 6, 7, 8, 9: Endless Eight. (Episode 16, 17, 18, 19, 20, 21, 22, 23) Being Erica (October 2010)
Season 3, Episode 4: Wash, Rinse, REPEAT. (Episode 29) Edge of Tomorrow (2014)
Film Doctor Strange (2016)
Film Star Trek: Discovery (October 2017)
Season 1, Episode 7: Magic to Make the Sanest Man Go Mad. (Episode 7)
Loops I Reject

Star Trek: Voyager (January 1997)
Season 3, Episode 15: Coda
Reason for Rejection: While Janeway and Chakotay think they're in a time loop for the first twenty minutes of the show, by the end it's revealed that the "loop" was really an entity screwing with Janeway's mind.

Farscape (April 1999)
Season 1, Episode 3: Back and Back and Back to the Future
Reason for Rejection: John isn't actually reliving the same moments in time so much as he was playing out "future flashes" in a sequence of visions. That said, this is a well done reversal of the genre.

Early Edition (December 1999)
Season 4, Episode 10: Run, Gary, Run.
Reason for Rejection: Gary injures his right hand on a plate to start the episode. This injury is only present in the last loop, confirming that the two prior instances were (shockingly realistic) dreams he was having - a fact the character himself comments on with the line "I'm awake. I'm definitely awake."

Andromeda (February 2003)
Season 3, Episode 12: The Dark Backward
Reason for Rejection: Upon further reflection, this episode is just Trance doing projections (like Farscape, above). That said, it is still noteworthy how, after cutting off a timeline where Harper dies, Trace is able to recreate it and see it to a later conclusion.

Smallville (January 2006)
Season 5, Episode 12: Reckoning
Reason for Rejection: Yes, Clark was able to go back in time and change things, but one day relived is not a time LOOP. (Same argument goes for the Angel episode "I Will Remember You".)

Totally Spies! (April 2006)
Season 4, Episode 12: Deja Cruise
Reason for Rejection: Considering the spies could watch their actions of the previous loops on surveillance equipment, this was hardly a time loop, just an elaborate ruse. No idea how they unsubmerged the ship.

The Librarians (December 2015)
Season 2, Episode 8: And the Point of Salvation
Reason for Rejection: It's revealed early on that they're actually stuck in a video game simulation, and looping back to a "save point". Which is damn clever, and with only Ezekiel remembering, it becomes an interesting study into loop psychology.

Cloak and Dagger (July 2018)
Season 1, Episode 7: Lotus Eaters
Reason for Rejection: Borderline between 'The Librarians' and 'First Wave', but placed here since time isn't actually looping. Tandy and Tyrone are inside Ivan's mind, which has been experiencing a loop for the past eight years. They try to break him out, with interesting consequences.

Loops I Have Not Seen

12:01 PM (1990) Short film - 30 min
A man keeps reliving the same hour over and over. This predates 'Groundhog Day'.

12:01 (1993) TV movie
Barry Thomas starts repeating the same day over from 12:01 in the morning; it just happens to be the same day a coworker he liked got murdered. Phelous (Phelan Porteous) does a 20 min analysis of the 12:01 movies here.

Charmed (Feb 2001) The Good, the Bad, and the Cursed
Apparently a murder victim from 1873 is stuck in a time loop, with time continuing outside the loop; they must go back to save him.

Dark Matter (June 2017) All the Time in the World
Three is the only one who knows about a time loop, and he needs to not only convince the others but figure out the reason why.

Happy Death Day (Oct 2017) Film.
Theresa "Tree" Gelbman wakes up on her birthday, and then keeps getting murdered and waking back up. She needs to figure out who is killing her in order to stop the loop, and alas, carries some of the physical trauma back with her upon awakening.

Happy Death Day 2U (Feb 2019) Film.
The sequel to "Happy Death Day" that finally explains Tree's loop as proximity to an experimental quantum reactor. This time she is knocked into a parallel dimension, and effectively relives the first movie, except here the killer is different AND she must choose whether to remain in this dimension (where her mother is alive) or return to her original one.

Russian Doll (Feb 2019) Netflix 8 episode series.
Nadia Vulvokov dies on the night of her 36th birthday, then keeps reliving the events in a time loop, dying differently every time. She then encounters a man, Alan, who seems to be experiencing his own loop, and they have to puzzle it out. (The series got a second season, but that involved time travel back 40 years, not strictly a loop.)

House of X: The Uncanny Life of Moira X (July 2019) Comic.
Dr. Moira McTaggert (nee Kinross), a supporting character in X-Men since 1975, was revealed in issue #2 to have had the power of "reincarnation", manifesting in an ability to return to her birth with all of her memories from her prior life. She loops her whole life, essentially, but seems limited to about 10 instances. This video analyzes her loops.

See also this wiki list of films featuring time loops.

Other sites about time loops: (for infinity loops) (for causality loops)

Other loop sites that link here thus allowing you to loop back:
The Shapiro Files: Of ... Time-Looping Films
Let's Do The Time Loop Again. And Again...
Halfbakery: Time Loops Game
Models of Time and Fate (ok, I wrote that)

Comments? Other loops that you know of? Let me know! cz159 "at" or email "mathtans" at gmail.
Last update: January 2023.

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